1. Field of the Invention
The present invention relates to a lamp assembly of a projector. In particular, the present invention relates to a lamp assembly of a projection apparatus having a function of adjusting the position of the lamp device.
2. Descriptions of the Related Art
There are various types of projection apparatuses on the market. A digital light processing projector (DLP), for example, comprises a reflector and an imaging device. The reflector consists of a lamp, a color wheel and an integration rod for projecting a uniform and concentrated light beam to the imaging device to produce an image at the output end. In fact, the reason why the scattering light provided by the above lamp can project uniform lights and increase light output efficiency is because the integration rod has a specific cross section. The cross section is generally in a shape of a rectangle as to produce a final rectangular image at the screen output. This cross section, in association with the light reflection resulted from the groups of reflecting mirrors disposed within the integration rod (called a “light tunnel”), make uniform lights and improved light output efficiency possible.
In view of the constraints of the small cross-section of the integration rod (i.e. limited light tunnel space), if the center of the principal projecting lights from the lamp device is off-center in view of the center of the cross section of the light tunnel, or deviates beyond the range defined by the light tunnel, the light beam uniformity and light output efficiency would significantly be compromised.
The DLP manufacturers and sellers may rely on their assembling techniques to adjust the center of the lamp's wick so that the front end coincides with the reflector at the rear end, thus, aligning the light source with the cross section of the integration rod. However, the adjustment procedure is very complicated and costly. When the lamp does not work, consumers have no means of replacement, and end up trying to maneuver the complicated adjustment themselves. Moreover, the professional technicians cannot precisely center the lights under the circumstance of no appropriate adjustment tools if they go to the consumers' place. Even if the whole projector is sent back to the dealer for repair, professional technicians must implement complicated adjusting procedures after the lamp is well repaired and replaced.
Nowadays, the DLP manufacturers and sellers are usually not the manufacturers of the lamp; instead, DLP manufacturers and sellers purchase lamps from the cooperative manufacturers for assembly. To keep costs down, the lamp manufacturers do not always consider the designing tolerance for being assembled to the projection apparatus. It follows that the center of the light beams coming from the light bulb and projecting from the back reflectors are significantly off-center from the cross-section center of the integration rod. This causes the obvious loss of light uniformity and brightness. To make up for the loss, in view of the foregoing descriptions, the technicians need to exercise a complicated adjustment and fixation for the alignment, both of which are not time- nor cost-effective.
Even simplifying the structure using related technology is not enough to solve the above problems. For example, the lamp adjustable apparatus of Taiwan Patent No. 547674 comprises a base, an adjustable module received in the base, an adjustable element and a returning element. The adjustable element and the returning element are placed on a surface opposite to the base. The adjustable module comprises a plurality of adjustable plates. The adjustable plates are combined with a plurality of guide holes and guide rods. One end of the lamp device is fixed on the adjustable module. The adjustable module can only be adjusted by combining the guide holes with the resilient guide rods of the adjustable plates. As can be seen, there are too many additional parts on the lamp cover, making it difficult and expensive to assemble. Furthermore, for both consumers and technicians, it is very difficult for them to replace the lamp with the required adjustments themselves.
In conclusion, the structures or apparatuses for adjusting the lamp device position in the prior art face problems of high lamp cost and assembling complexity. Therefore, it is very important for manufacturers to use simpler mechanical designs to reduce the difficulty in lamp device adjustment, specifically with respect to the precise alignment between the light projection and the light tunnel. In addition, it is important for users to purchase a lamp module which has already been adjusted and positioned by the dealers and is ready for assembly on to the optical engine, thereby controlling the costs.